Research On Promoting Gas-liquid Separation Of CO₂ Flooding Crude Oil By Ultrasound

CO₂ flooding technology can effectively improve the oil recovery,but the CO₂solubility in the crude oil is higher than conventional associated gas.Crude oil flooded by CO₂ technology will contain a large amount of CO₂.The conventional gas-liquid separation technology or methods such as extending residence time in the separator,cannot achieve the complete separation of CO₂ and oil and will cause severe corrosion to the follow-up equipment.And there will be a lot of foams in the process of separation,causing more complicated separation problems.Therefore,it is of great significance to explore the gas-liquid separation characteristics of CO₂ flooding crude oil and find a method to promote the gas-liquid separation of CO₂ flooding crude oil to solve the difficulties in the surface gathering and transportation system of CO₂ flooding oilfield.On the basis of analyzing the process of gas-liquid separation of CO₂ flooding crude oil,the motion characteristics of cavitation bubbles under ultrasonic field were simulated by MATLAB,and the influence rules of initial radius of bubbles,ultrasonic frequency and power on cavitation were obtained,which provided theoretical guidance for ultrasonic wave to promote the gas-liquid separation of CO₂ flooding crude oil.The design and construction of a dynamical experimental device for improving gas-liquid separation of CO₂ flooding crude oil by ultrasonic wave were completed.The conventional gas-liquid separation process of crude oil in a gas-liquid separator was simulated under the conditions of gathering and transportation temperature and pressure with the method of decompression and desorption.Without ultrasonic,analyze the main factors influencing the gas-liquid separation properties,determine the variation of CO₂desorption rate with residence time,pressure drop and the inlet components to get the best conditions of gas-liquid separation of CO₂ flooding crude oil.It has been clear that the carbon dioxide cannot completely desorb from crude oil by the conventional step-down desorption method.Under the optimal condition of gas-liquid separation,apply the ultrasonic to the measurement of CO₂ desorption rate changes with ultrasonic power and frequency,to verify the numerical simulation results and make sure that the ultrasonic can promote the gas-liquid separation of CO₂ flooding crude oil.And the influence of ultrasonic frequency and power on the gas-liquid separation effect of CO₂ flooding crude oil.